1. Field of the Invention
The present invention relates to a lithography technology, and in particular, to an exposure method, an exposure tool which use a liquid immersion method, and a method of manufacturing a semiconductor device.
2. Description of the Related Art
In recent years, in order to cope with the miniaturization of semiconductor device patterns, a liquid immersion exposure tool in which exposure is carried out in a state in which a space between a projection lens and a to-be-substrate (hereinafter, substrate) is filled with a liquid immersion medium fluid (for example, water) has been developed (WO 99/46504). An exposure tool is made to be liquid immersion type, so that it is possible to improve a limit to a resolution without a change of an exposure wavelength, or to magnify a depth of focus. On the other hand, there are concerns that, a surface of a resist film is exposed to a liquid immersion medium fluid, whereby a substance is generated from the resist film due to hydrolysis or a photochemical reaction in the course of exposure, and the generated substance diffuses in the liquid immersion medium fluid, which scatters an exposure light, or contaminates a lens.